Process of vulcanizing rubber



NoDrawing.

Patentedluly 18, 1933 UNITED STATES 1,918,328 PATENT OFFICE HARRY L. FISHER, OF LEONIA, NEW JEBSEY ASSIGNOR TO THE NAUGATUCK CHEMI- CAL COMPANY, OF NAUGATUCK, CONNECTICUT, A CORPORATION OF OONNMTIC'UT I PROCESS OF VULCANIZING RUPBEE This invention relates to processes of vulcanizing rubber and similar vulcanizable materials and to the resulting products. More particularly it has to do with new vulcanizing agents and their use in rubber.

The materials knowirto cause the vulcanization. of rubber are numerous, chief among them being sulphur. This material, however, while universally used, is not suitable for every occasion. Sulphur vulcanizates, for instance, tarnish metals such as copper, silver, etc., and where such vulcanizates are used for rubber-metal objects, for instance composite rubber and metallic cloth or fabricarticles, rubber-insulated wire, head .lights, silverware, copperware, etc their disadvantage is manifest. Furthermore the use of sulphur as a vulcanizin agent, in the absence of vulcanization acce erators, requires a long time to vulcanize rubber and rubberdi'ke bodies.

An object of this invention is to obviate the use of sulphur and accelerators, by supplying a vulcanizing agent that overcomes the above disadvantages and provides a series of products having a wide range of de-' sirable physical characteristics. Further objects and. advantages will be apparent from the hereinafter set forth descri tion. I

The new vulcanizing a ents are roadly quinone compounds containing halogen attached to'the quinone nucleus, and more particularly such compounds derived from pbenzoquinone. Some of the compounds op-' crate favorably as vulcanizing'agents either with or without the aid'of an oxidizing agent, while others require the aid of an oxidizing agent. The preferred oxidizing agents are those containing oxygen and a multi-valent metal, for example, lead peroxide, manganese dioxide,-mercuric oxide, lead chromate, etc., which the multivalent ,metal combined with the oxygen is in a high- 46 er state of oxidation.-

The halogen substitution and addition products of the. quinone compounds are designated quinone haloids and are to be understood as including halogenated quinones, halogenated quinhydrones, halogenated hydroqninones, addition products of a quinone and ahalogen, or any mixture thereof.

The halogenated quinon'es may be added directly to the rubber or rubber mix or al- Application filed August 20, 1931. Serial No. 558,884.

ternatively may be formed in the rubber by adding the corresponding halogenated'hydroquinones, quinhydrones, or'quinone hal ides, and an oxidizing agent to the rubber and vulcanizing. I

In every case the actual vulcanizing agent appears to be a halogenated quinone, wheth er added to the rubber as such, or formed in the rubber by the oxidation of auinone haloid of a reduced type, such as a alogenated hydroquinone. During the course of vulcanization by means of a halogenated quinone in the absence of an oxidizing agent, one-half of the quinone added becomes reduced to the corresponding halogenated hydroquinone, is then incapable of combining with the rubber, and is extractable by acetone. In the presence of an oxidizing agent, however, such hydroquinone is immediately oxidized, whereb the quinone is continuously regenerated, thus making possible the effective use as a vulcanizing agent of all the quinone originally added. In such case the acetone extract of the resulting vulcanized product contains substantially no halogen, indicating that substantially all of the halogenated quinone originally added is combined with the rubber.

Examples of halogenated quinones are, monochloro-p-benzo quinone, 2,3-dichloro-pbenzoquinone, 2,5- dichloro-p-b'enzoquinone,

chloro-p-toluquinone, tetrabromo o benzoquinone, tetraiodo-p-benzoquinone. The materials us'ed may'be pureor impure and contain varying percentages of halogen. Mixtures of the higher chlorinated p benzoquinones containing tetra-chloro-p-benzoquinone in va 'ing amounts and having melt-r ing points tween approximately 195 and approximately 285 C. are especially desirablesince they may be prepared in finely divided form, are non-volatile, show no p01- vsonous properties, and may be usedto vulcanize rubber in the presence or absence of an oxidizing agent.

The compounds may be prepared in any known manner. The following is illustrative of a new and 'fine yellow precipitate which has been formed has risen to the topof the reaction mixture. The chlorination has by then (about 10 hrs.) proceeded through several stages of lower chlorinated products to a conclusion, forming finally tetrachloro-pbenzoquinone which is in the form of the said yellow precipitate. This materialis separated by filtration, washed and dried. The filtrate if desired may be used as a reaction medium for the preparation of more tetrachloro-p-benzoquinone. The yield is nearly quantitative and -the material melts between 267275 C. When pure it has a melting point of about 289 C. The process may be varied to form lowerchlorinated products as will be apparent and other agents such as potassium permanganate,.

sodium or potassium dichromate with or without sulphuric acid, may be used instead of the chromic anhydride. Ferric chloride hasbeen found effective in carrying the reaction as far as the formation of tetrachlorohydroquinbne in practically quantitative yields, substantially none of the corresponding chlorinated quinones being formed.

The examples given below are illustrative of the invention, but are not to be construed as limiting thereof (parts are by weight) Example 1 Rubber 100 100 Tetrachloro-p-benaoquinone 5 'C- 4 Vulcanized In a press at 141 C. '1 E T E 16 min 900 880 850 940 90 min 025 890 poo 95o T-tensile strength. lbs. per sq. in. E=% elongation at break.

Example 2 Rubber zoo "100 100 Monochloro-p-benzoquinono 6 10 15 Vulcanized in a press at 141 C. '1 E T E p T E 30 min 518 860 l. 257 780 wmin Q. 978 860 1,190 870 U) min. 255 l, 030] 804 800 l, 276 780 Example 3' Rubber i 100 100 Tetrabrommp-benzoquinone 5 1O Vulcanized in a press at 141 C. T E T E 5 min 1053 900 10 mllL--. 1102 770 1256 740 20 mm 960 1271 830 The corresponding quinhydrones may be used in place of the halogenated quinones, and behave as if the corresponding quinone and hydroquinone were present.

Example 4 The effectiveness of the vulcanizing agents is enhanced in the presence of oxidizing agents (as indicated more fully below), such forexample as lead peroxide:

The new vulcanizing-agents are also effective in the pr esence of rubber compounding materials as illustrated below:

Emdmplq 5 Pale crepe 100 Tetrachloro-p-benzoquinone (M. P 284 C.)- L 5 Whitin I00 Vulcanized in a press at 141 O. '1 E 30 min 1900 610 60 min 2166 620 90 min 2345 510 Example 6 Pale crepe i 100 Vulcanized in a press at Chlorinated -benzoquinone 5 15 min. 3005 610 (M. P. 225-: C. 53.02% Cl) 30 min I) 640 G0 min 3045 580 90 min. 3030 570 Zinc oxido 100 i Example 7 Pale crope- 100 Vulcanized in a press at 141 C.

Chlorinatedp-beuzoquinone 4 15 m n 2207 780 (M. P. IDS-215 C. 49.05% Ci) 4 60 min 2220 750 90min. 2267 730 Zinc oxide 5 Bar 40 Boric acid 5 Eaample 8 Emample 14 Palecre 100.0 Wra dar d dmplpemld0137111ll caml l zg Pale crepe 100 vzflcanizffignoepressat 1n soapstone at 141 C. I 5 7o '1 a Trlchloro-p-toluqulnone 5 Chlorlna uinono. 5.5

M. P. 195411904905 01-. so 111.... m2 400 aomm-m gvhit 100.0 m gma.-- 1593 410 180111111... 1041 440 10 gmg g3 9 Pafllmll 1.1 Ewample 15 Leadperoxide 22.2

Emple 9 Pale crepe. 100.0 Vulcanizodinapress at 0 Chlorinated -benmqulnone-.' 4 v x (M. P. 225-1 0., 53.02% 01 15111111.--. 2113 s70 30min.- 2357 660 Red oxide ofiron 00 2167 540 min-.-- ms 500 Silica dust ao Clay 25 25 Emmrple 10 Smoked sheet vulmnllfiisgn n press I Tetraiodo-p-benzoquinone 10 T E l Zlncoxlde 100 120m... 1052 010 80 T, E g Chlorinated p mm (M 6 30mm 3505 m Examples ofehalogenated hydro 'uinones P. -215 o.,4o.oa% 01 eommIIII 35:41 300 are, monochlono-hydroqulnone,2,5- 1chl0ro- M 2 2. E hydroqumone, 2,6- dlchlorohydroqumone,

1 trlchloro-h d-ro uilnome tetrachloi'o-h droqumone, monobromo-hydroqumone, 2,5-d1- bromo hydroqumone 2 6-d1brom0-hydro- Eammple 11 I qumone, tubmmo-hydroqumone, and tetrabro mo-hydroqumone; these groducts as well Pm mp0 m j m as the halogen-additmnpro ucts such as p- 10 benzoqulnone-dlchlonde and p-benzo ul- T E none-dlbromlde when used asvulcanlzmg agents should be used in con unct1on v v1th gfgg gg'ggj 30min m an oxldlzlng agent such as lead peroxlde 0r 5 gaggig the hke, thereby efiectmg the formatlon of the correspondlng halogenated qumone 1n "9 the rubber before or dunn vulcamzatlon. Eammple 12 g Vanous oxldlzmg agents other than lead peroxlde, e. g. manganese dloxlde and mer- 50 Pm ff j m v curlc oxlde, have been found to functlon ef- I 7 ficlentl when used in con unctlon wlth the y 1 T E lower halogenated hydroqulnones, partlcularl 71th the mono-halogen hydroqulnones, a'wkmwp'mm 5 as 1 ustrated m Examples21 and 22 below.

The use of such matenals 1s Illustrated by the followlng examples:

Ewwmple 17 mg 10: 1o:

'r n 'r' -E 'r E 'r E zb-dlohloro-p-bensouuinone 5 m cm Zlncoxide ..-.x 100 oommIIII ms 040 ao'nlmo 2m 1m mo no e05 830 '5 comm--- no: no Wot141O...- am cm 1040 an am am Example 1 8 Pale crepe. 100 Vulcanized in a press at Trichloro-hydroquinone 4 141 C.

Lead peroxide 15 15 min. 987 720 30 min 1643 650 90 min- 2050 600 Emample 19 Pale crepe 100 Vulcanized in a press Trichloro-hydroquinone 5 at 141 C. Manganese dioxide .7 5

v i 'r r:

30 min 360 970 60 min. 106.5 830 90 min 1435 i 800 Exam pic 20 Pale crepe 100 Vulcanized in a press '1etrabromo-hydroquinone. 6 at 141 C. Lead peroxide 15 15 min 588 500 60min 1147 640 90mi11 1703 670 Example 21 Pale crepe 100 Vulcanized in a press Monochloro-hydroquinone. 7. 5 at 141 C Manganese dioxide l5 30 min 2167 690 60 min 2184 640 90min. 2181 680 Example 22 Rubber 100 100 Monobromo-hydroquinone .1 5 1n Manganese dioxide 10 10 '1 E T E Pale crepe 100.0 Calendered and wrap- Ietrachloro-hydroquinone. 5. 5 ped around a man- Whiting 100.0 drel, and vulcanized Lamp black 2. 2 in soapstone at 141 0. Lead peroxide 22. 2

60 min... 1852 410 120 min 1835 390 180 min 1815 390 Example 2!;

Smoked sheet 100 Vulcanized in a press at Tetrachloro-hydroquinone 5 141 Carbon black 50 20 min. 3255 440 Lead peroxide 7 15 40 min. 2920 400 Laurie acid 5 60 min 3173 410 90 min 3367 420 In place of the halogenated hydro-quinones, salts thereof may be used, such, for example, as the zinc, calcium, magnesium, or sodium salts. Such salts as the mercuric salts may also be used, in which case the salt is self-oxidizing and no additional oxidizing agent is required.

Example 25 Rubber 100 Vulcanized in a press at p-bcnzoquinone dichloride '1 E 30 min 60 min 90 min Lead peroxide 01 l (rearrangement) H ---P Cl 1 i i 0 on o The new vulcanizing agents are effective over a \vlde range of temperatures, as shown by the following data:

1A ,B C

Pale crepe 10O 1 100 Tetraehloro-p-benzoquinone (M. P. 267 C.,54.7%C1). 4 4 4 Zinc oxide 100 Lead perioxide. 10

Times of vulcanization Minutes Temp. Comoivulpound can- 10 20 30 60 120 17.3- tion "1 E '1 E '1 E '1 E T E C. A 108 V "use." 531 9.2 890 9.8 91810.6 121 76810.1 82710.1 703 9.9 587 9.4 658 9.5 141 885 9.6 85 4.1 270 6.6 1290100 783 8.2 153 475 9.4 777 9.9 82410.3 162 79310.1 229 9.2 69110.2 649 9.9 519 9.3

121 1273 8.1 1821 6.8 2503 6.8 2768 6.2 3052 6.1 IQS 141 1975 5.7 2867 5.9 3027 5.8 2057 4.9 2502 5.1 153 3082 6.6 2285 5.4 2831 5.5 1509 4.2 2281 5.0 162 2595 5.7 2360 5.3 2198 5.1 .1435 4.2

The higher halogenated products, such as tetrachloro-p-benzoquinone, have been found 1:10

- room temperatures.

to effect satisfactory vulcanization even at For example a stock consisting of 100 parts of pale crepeand 5 parts of tetrachloro-p-benzoquinone was calendered to a sheet 0.062 inch in gauge, and

was then laid aside at room temperature for several months. At the end of five months the sheet was found to have become well vulcanized having a tensile stren h in the direction of the calender grain o 1168 lbs., and aneIongation at break of 770%. After a total of 6 months the tensile strength had increased to 1567 lbs., the elongation being 780%. I

The new vulcanizing agents are especially advanta eous in the production of vulcanized rub er-coated fabrics wherein the rubber surface is varnished. The life of the varnish, and articularly its resistance to cracking and c ecking, are. greatly increased by virtue of the absence of sulphur." When the rubber compounds contain large proportions of reclaimed rubber, .the resulting vulcanizates are superior inphysical properties to similar compounds cured with sulphur and accelerators.

A certain'amount of blooming in the form of a whitish substance on the surface of vulcanizates attends the use of the higher halogenated quinones, which bloom cdnsists essentially. of reduction products, namely,

' the corresponding halogenated hydroquinones, but this may be obviated by using the hologenated quinone in conjunction with an oxidizing agent such as, for example, lead peroxide, mercuric oxide, etc., which apparently also play the part of activators for the vulcanizing agents. Ma esia, slaked lime, litharge, have also been ound efiective in reventing formation of such bloom.

trong alkalies and or anic amines such as sodium hydroxide, anillne, etc., in the absenoe of oxidizing agents, tend to destroy the vulcanizing activity or effect of the new vulcanizing agents by reacting therewithto form compounds which exhibit little or no vulcanizing action, and this fact should be taken into consideration in designing rub ber'compounds employing the new" vulcanizing agents. Such 0s 0 vulcanizin activity ma be obviated by either eliminating such a kalies or amines or limiting their n amounts, or by the agent.

addition of an oxidizing Ordinarily 3 to 5 parts. of the new vull canizing' agents may be used to effectvulcanization, but this amount may vary in accordance with the type of rubber and compounding in 'edients, for example in highly oompoun ed stocks it ma be desirable to use as high as 10 parts oft e vulcanizing agent.

The new'vulcanized roducts have many of the properties of ru ber-sulfur vulcanizates, for example,they possess tensile strength; they are practically insoluble in the ordinary rubber solvents; the show at 0 C. substantially the same resi ience and elongation as at room temperature; and by proper compounding with carbon black,

zinc oxide, and/or other fillers they. can be a production of various composite rubber articles or goods. For example the vulcanized latex threads or "filaments maybe wound with yarn or thread or other materials for the making of various articles such as gaiters,'which employ metal attachments, or intermeshed as by weaving or knitting into association with metallic threads as 1n the making of so-called metallic cloths or fab rics. Because-the rubber produced is free the formation-of metal sulphides, such as occurs through :contact or proximity of themetal to sulphur-containing rubber, avoided. r

The halogenated hydroquinones, in conjunction with oxidizing agents, have been found particularly eflicaious for use in la tex. They are sol'uble in the presence of the -fromsulphur, tarnishing of the metals by small amount of ammonia contained in ammonia-preserved latex, and the also assist in the dispersion of the oxidizing agents employed therewith. y A

When the new vulcanizing agents are em-' ployed in the vulcanization of latex as such, the result'in vulcanized latices have the a. pearanc'e o thixotropic gels, and may spread or otherwisev deposited in known manner and dried to producecoatings of vulcanized rubber.

The materialsma be applied for the vulcanization ofrub r broadl including caoutchouc, balata, gutta-perc a, synthetic rubber, natural latex orartificially prepared latex, and in conjunction with any of the usual compounding ingredients including softeners, anti-agers, fillers, etc. While the' invention has todo with new vulcan' iz;

ing agents for the vulcanization of rubber they may .be used to supplement the usua vulcanization with sulphur, if desired. while certain preferred oxidizing-agents have been mentioned herein, other oxidizi agents may-be used, for example, red lea oxide, thorium oxide, nickelic oxide, cobaltic oxide, ferric vanadate, ferric phosphate,

'ferric sulfate, ferric oxalate, ferric benzoate.

With the detailed disclosure above, it will be evident that numerous modifications will suggest themselves to those skilled in the I art, without-the exercise of invention there- .canization of the rubber by means of 310 parts by weight based on the rubber of a quinone haloid having a single ring structure as a vulcanizing agent.

3. A process of producing vulcanized rubber products which comprises effecting vulcanization of the rubber by means of a quinone haloid having a single ring structure and an oxidizing agent.

4. A process of producing vulcanized rubber products which comprises effecting vulcanization of the rubber by means of: a

- quinone haloid having a single ring structure and an oxidizing agent containing oxygen and amultivalent metal.

5. A process of producing vulcanized rubber products which comprises effecting vulcanization of the rubber by means of 3-10 parts by weight based on the rubber of a quinone compound containing halogen attached to the quinone nucleus as a vulcanizing agent, the .temperature of treatment being such as to require not more than about three hours for proper vulcanization of the rubber. 5

6. A process of producing vulcanizedrubber products Which comprises effecting vulcanization of the rubber by means of 3-10 parts by weight based on the rubber of a halogenated benzoquinone as a vulcanizing agent, the temperature of treatment being such as to require not more than about three hours for proper vulcanization of the rubber.

o 7. A process ofproduciiig vulcanized rubber products which comprises effecting vulcanization of the rubber by means of 3-10 parts by weightbased on the rubber of a chlorinated benzoquinone as a vulcanizing agent, the temperature of treatment being such as to require not more than-about three hours for proper vulcanization of the rubber.

8. A process of producing vulcanized rub-.

' ber products which comprises effecting vulcanization of the rubber by means of 3-10 parts by weight based on the rubber of halogenated-p-benzoquinone as a vulcanizing.

canization of the rubber by means of 3-10 part-s by wei ht based on the rubber of chlorinated p enzoqnlnone as a vulcanizlng agent, the temperature of treatmentbeing such as to require not more than about three hours for proper vulcanization of the rub ber.

10. A process of producing Ivulcanized rubber products which comprises effecting vulcanization of the rubber by means of 3-10 parts by weight based on the rubber of chlorinated p-benzoquinone melting between approxiniately 195 C. and approximately 289 (3., the temperature of treatment being such as to require not more than about three hours for proper vulcanization of the rubber. v

11. A process of producing vulcanized rubber products which compri'seseffecting vulcanization of the rubber by means of 310 parts by weight based on the rubber of tetrachloro-p-benzoquinone, the temperature of treatment being such as to require not more than about three hours for proper vulcanization of the rubber.

12. A process of p'roducing vulcanized rubber products which comprises effecting vulcanization of the rubber by means of chlorinated p-benzoquinone melting between approximately 195 C. and approximately 289 C., and an oxidizing agent containing oxygen and a multivalent metal. I

13. A process of producing vulcanized rubber products which comprises effecting vulcanization of the rubber by means of chlorinated p-benzoquinone melting be-- 17. A process of producing vulcanized rubber products which comprises effecting vulcanization of the rubber by means of a halogenated hydroquinone and an oxidizing vulcanization of the rubber by means 0 tetrachlorohydroquinone and an oxidizing agent containing oxygen and a multivalent metal.

2!). A process of roducing vulcanized rubber products which comprises efiectin vulcanization of the rubber by means .0 tetrachlorohydroquinone and lead peroxide.

21.. A. process of producin vulcanized rubber products which com rises effecting vulcanization of the rubber y meansof an addition product of a halogen and a quin one having a single ring structure, and an oxidizing agent.

22. A process of roducing vulcanized rubber products whic com rises effecting vulcanization of the rubber y means of an addition product of a halogen and a. uinone having a single ring structure, an an oxidizing agent containing oxygen and a multivalent metal.

23. A process of producing vulcanized rubber products which comprises efl'ecting vulcanization 0f the rubber by means of an addition product of a halogen and p-benzoquinone, and an oxidizing agent.

24. A process of roducing vulcanized rubber products whic comprises efiectin vulcanization of the rubber by means 0 an addition roduct of chlorine and p-benzoquinone, and an oxidizing agent 25. A process of producmg vulcanized rubber products which comprises effectin vulcanization of the rubber by means ,0 an addition product of a halogen and pbenzoquinone, and an oxidizing agent containing oxygen and a multivalent metal.

26. A process of producing vulcanized rubber products which comprises eifectin vulcanization of the rubber by means 0 a an addition product of chlorine and p-benzoquinone, and an oxidizing agent containing oxygen and a multivalent metal.

27. A process of producing vulcanized rubber products which comprises efiecting vulcanization of the rubber by means of p-b enzoquinone dichloride and an oxidizing ageng containing oxygen and a multivalent meta 28. A 1 process of roducing vulcanized rubber products whic comprises efiectin vulcanization of the rubber by means 0 pl-benzoquinone dichloride and lead perox- 1 e.

29. A vulcanized rubber product obtained according to the process set forth in claim 2. 30. A vulcanized rubber product obtained according to the process set forth in claim 5. 31. A vulcanized rubber product obtained according to the process set forth in claim 6. 32. A vulcanized rubber product obtained according to the process set forth in claim 7.

33. A vulcanized rubber product obtained according to the process set forth in claim 8. 34. A vulcanized rubber product obtained according to the process set forth in claim 9. 35. A vulcanized rubber product obtained pgcording to the process set forth in claim 36. A vulcanized rubber product obtained according to the process set forth in claim 11.

37. A vulcanized rubber product obtained according to the process set forth in claim 13.

38. A vulcanized rubber product obtained according to the process set forth in claim 15.

39. A vulcanized rubber product obtained according to the process set forth in claim 18.

40. A vulcanized rubber product obtained according to the process set forth in claim 22. i

41. A vulcanized rubber product obtained according to the processset forth in claim 23.

42. A vulcanized rubber product obtained according to the process set forth in claim 24. I

43'. A vulcanized rubber product obtained according to the process set forth in claim'26.-

44. A composite rubber and metal article in which the rubber has been vulcanized by means of a quinone haloid having a single ring structure.

45. A fabric material comprising metallic 3 threads associated with latex threads or filaments that have been vulcanized by means of a halogenated p-benzoquinone.

quinone.

HARRY L. FISHER. 

